A Machine Type Communication (MTC) is one type of data communication and refers to communication between devices or objects (Machine to Machine (M2M) communication) with minimal human interaction or without human interaction.
A User Equipment (UE) used for MTC may periodically transmit/receive data to/from an MTC application server through a mobile communication network. A UE used for MTC has a time tolerant characteristic or a delay tolerant characteristic. Such a delay tolerant UE for MTC is processed with a lower priority compared to a general UE in Non-Access Stratum (NSA) signaling, so that a mobile communication service provider can efficiently accept a large amount of MTC devices. To this end, 3rd Generation Partnership Project (3GPP) defines device property IEs for processing NAS signaling with a low priority and defines specification that may reject preferentially the NAS signaling having the low priority when overload is generated in the network. Configuration information for the NAS signaling having the low priority may be allocated to each device. That is, the UE for MTC may be configured to have one of a low priority and a normal priority.
Meanwhile, although the UE for MTC is configured to perform the NAS signaling with the low priority, the UE for MTC may be required to make access with the normal priority in case of specific conditions. For example, an electric meter is configured to transmit a report with a low priority. However, when an emergency is detected, (e.g., when the device is being stolen), the electric meter may desire to transmit an alarm signal thereof with the normal priority. In this case, the network may not be able to process the emergency signal.